• 동력기계공학회지
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• 제22권6호
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• pp.58-66
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• 2018

The use of external gear pumps is an effective way to achieve adequate performance at low cost when composing hydraulic systems. The biggest drawback, on the other hand, is the accompanying noise. Gears of continuous contact shape are actively used for the pump recently. The continuous contact shape must be the helical type due to the nature of the gear pump that is driven only by the drive gear. In this paper the theoretical shape of continuous contact gear is analyzed using simple rack shape of straight lines and two circular arcs. Using such geometry, the theoretical equation will be developed by envelope curves according to the conjugate gear shape rules. After checking the validity of the theory by the shape of gear rules, the grinding shape was also developed. The 3D shapes using equation can be also drawn. It was also shown that contact ratio and radius of curvature are easily developed by the theoretical equations.

• 대한조선학회논문집
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• 제31권4호
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• pp.139-146
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• 1994

본 논문에서는 선상가열법을 이용한 강판의 곡가공 자동화를 향한 하나의 가능성 있는 방향을 제시하고 있다. 이를 위해 선상가열현상을 대변할 수 있는 역학적 모델을 도입하여 가열조건들이 주어져 있을 때 가열경로를 구할 수 있는 알고리즘을 소개하였고 이에 의거해서 컴퓨터 프로그램을 개발하였다. 이의 정당성을 확인하기 위해 개발된 컴퓨터 프로그램을 2가지 형태의 곡면형상에 적용하여 이를 가공할 수 있는 가열경로를 찾는 시도를 해 보았는데, 이로부터 본 논문에서 제안하는 알고리즘과 프로그램 시스템은 만족할 만한 결과를 주고 있으며, 이는 곡가공 자동화 시스템 구축을 향한 합리적인 길이 될 수 있음을 확인할 수 있었다.

• 동서간호학연구지
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• 제24권2호
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• pp.171-181
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• 2018

Purpose: The study aimed to validate a structural model of self-concept among children and adolescents from multicultural families. Methods: Data were collected from 325 mothers of multicultural families and their 417 children. Confirmatory factor analysis, path analysis and multiple mediation analysis with a phantom variable approach were used to assess construct validity and relations between model variables. Results: Goodness of fit indices of the modified theoretical model, the standardized ${\chi}^2$ (2.75), RMR (.02), RMSEA (.07), NFI (.90), TLI (.92), CFI (.94), GFI (.89), and AGFI (.87), met criteria. Social support and mental health problem had significant direct effects on self-concept, whereas residential environment and school adjustment had significant indirect effects, accounting in combination for 53% of the variance in self-concept. Conclusion: Based on the results, mental health problem mediated the relationships of self-concept and parenting stress.

• 국제강구조저널
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• 제18권4호
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• pp.1139-1152
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• 2018

Many studies on the application of stainless steels as structural materials in buildings and infra-structures have been performed thanks to superior characteristics of corrosion resistance, fire resistance and aesthetic appeal. Experimental investigation to estimate the ultimate strength and fracture mode of the fillet-welded connections of cold-formed austenitic stainless steel (STS304L) with better intergranular corrosion resistance than that of austenitic stainless steel, STS304 commonly used has carried out by authors. Specimens were fabricated to fail by base metal fracture not weld metal fracture with main variables of weld lengths according to loading direction. All specimens showed a block shear fracture mode. In this paper, finite element analysis model was developed to predict the ultimate behaviors of welded connection and its validity was verified through the comparison with test results. Since the block shear behavior of welded connection due to stress triaxiality and shear-lag effects is different from that of bolted connection, stress and strain distributions in the critical path of tensile and shear fracture section were investigated. Test and analysis strengths were compared with those by current design specifications such as AISC, EC3 and existing researcher's proposed equations. In addition, through parametric analysis with extended variables, the conditions of end distance and longitudinal weld length for block shear fracture and tensile fracture were suggested.

• 전력전자학회논문지
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• 제26권3호
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• pp.176-182
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• 2021

This research proposes a high-frequency circuit that can accurately predict the differential mode noise of single-phase inverters at the circuit design stage. Proposed single-phase inverter high frequency circuit in the work is a form in which harmonic impedance components are added to the basic single-phase inverter circuit configuration. For accurate noise prediction, parasitic components present in each part of the differential noise path were extracted. Impedance was extracted using a network analyzer and Q3D in the measurement range of 150 kHz to 30 MHz. A high-frequency circuit model was completed by applying the measured values. Simulations and experiments were conducted to confirm the validity of the high-frequency circuit. As a result, we were able to predict the resonance point of the differential mode voltage extracted as an experimental value with a high-frequency circuit model within an approximately 10% error. Through this outcome, we could verify that differential mode noise can be accurately predicted using the proposed model of the high-frequency circuit without a separate test bench for noise measurement.

• Journal of Korea Trade
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• 제23권7호
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• pp.64-82
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• 2019

Purpose - This study's the ultimate goal is to analyze competitiveness improvement on multinational enterprises as firstly providing which factors are to strengthen or weaken competitiveness, secondly investigating if hypotheses development and research design is correct and thirdly finding significant implications for research and practices across country specific advantage. Design/methodology - Using feedback data provided by 250 firms, we extracted variable factors and hypotheses, which were empirically carried out by reliability and validity testing, correlation analysis, path analysis, and confirmatory factor analysis to prove which factors are to make the positive effect on the improvement of overseas subsidiaries' management performance and competitiveness. Findings - Through proceeding empirical analysis study, we found out that technology management capability, knowledge management capability, and local management capability had a statistically significant effect on the improvement of overseas subsidiaries' competitiveness, while linked activity capability revealed a negative effect. Originality/value - During business globalization, overseas investments and establishment of overseas subsidiaries have been essential. It is anticipated that this study results would be meaningful for analysis on multinational enterprises' competitiveness and helpful in promoting their entry into Korean market and enhancing their competitiveness. This paper would also help Korea government develops new FDI model and induce more investment from global major companies to Korea region.

• 산경연구논집
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• 제14권3호
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• pp.27-43
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• 2023

Purpose: Changes in the employment environment in the era of the 4th Industrial Revolution are influencing various factors by the emergence of new jobs and the change in perception of job stability due to globalization of information technology and industry This study attempted to present implications by verifying the structural relationship of beauty workers' sustainable organizational commitment and the method necessary for conflict management in the industrial field due to the recent changes in the employment environment of the beauty industry in the 4th Industrial Revolution. Research design, data and methodology: This study sampled 604 beauty industry employees Frequency analysis, validity and reliability analysis, factor analysis, and path analysis were performed using SPSS WIN23.0. Results: It was found that the change in the employment environment caused by the 4th industrial revolution had a significant negative (-) effect on the job satisfaction and organizational commitment of beauty industry workers. Conclusion: This study is that changes in the employment environment negatively affect job satisfaction and organizational commitment of beauty workers. We hope to contribute to the development and growth of the beauty industry by providing basic data for the beauty tech service industry in the 4th industrial era.

• 유통과학연구
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• 제20권11호
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• pp.99-108
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• 2022

Purpose: The wide distribution of smartphones has changed life and user behavior. This phenomenon has both advantages and disadvantages for users. As smartphones become a part of our daily lives, smartphone addiction has recently become a social issue in many countries. This study explores factors that affect smartphone addiction and the consequences of addictive behaviors. Research design, data and methodology: Our model hypothesizes that four key factors determine addictive behavior: flow, enjoyment, preference for online social life, and escape reality. Commitment and compulsive use are mediating variables that connect key drivers and addictive results. Based on the SEM (structural equation model) analysis of 497 survey responses, these four driving factors each have a significant effect on the compulsive use of smartphones directly or indirectly; the compulsive use of smartphones directly influences the three results Results: We conducted a reliability and validity analysis, and the results were successful. In the hypothesis test, every path is accepted as expected at the significance level of 0.05. Conclusions: Among the four driving factors, escape reality is the vital factor influencing smartphone addiction and its consequences. And anxiety is the number one consequence influenced by the compulsive use of smartphones.

• 한국치위생학회지
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• 제23권4호
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• pp.323-331
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• 2023

Objectives: This study was conducted to confirm the relationship between role conflict, positive psychological capital, and the psychological well-being of dental hygienists and to provide data for improving professionalism by increasing the psychological well-being of dental hygienists. Methods: From May 21 to June 22, 2023, 190 data were collected through an online community of dental hygienists. The collected data were analyzed IBM SPSS program ver. 23.0 and AMOS ver. 26.0. Statistical analysis methods, convergent validity test, structural equation model analysis, and model fit were performed using independent sample t-test, one-way ANOVA, confirmatory factor analysis, structural model fit test, and path analysis. Results: The lower the role conflict of dental hygienists and the higher the positive psychological capital, the higher the psychological well-being. The lower the role conflict, the higher the positive psychological capital. However, there was no mediating effect between positive psychological capital and role conflict, as it was not statistically significant. Analysis of the total effect of role conflict and positive psychological capital on psychological well-being revealed that positive psychological capital had a greater influence on psychological well-being than role conflict. Conclusions: Psychological well-being was related to positive psychological capital and role conflict. Future efforts are needed to improve positive psychological capital and psychological well-being of dental hygienists and reduce role conflict.

• 의학교육논단
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• 제26권1호
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• pp.48-54
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• 2024

The career choices of medical students are significant for both individual students and society, which relies on a robust public healthcare system. Medical schools should provide a conducive environment and diverse information to enable students to make mature career decisions. Yonsei University College of Medicine conducts extracurricular programs for students' career development, including the Career Choice Expo, Career Path Survey, Special Lecture on Career Development, and a Visible Radio Show focused on career counseling. Additionally, the intracurricular activities offered by the college include career advising to students through faculty advisors in learning communities based on students' reflective writing about career-related activities. Medical students, in the process of forming their career decisions, compare what they have learned in the medical school curriculum with information acquired through extracurricular activities, taking into consideration their individual characteristics. Through longitudinal discussions with faculty advisors in learning communities, medical students not only gain recognition for the validity of their exploratory activities but also develop a sense of self-efficacy in making career decisions. The career education program at Yonsei University College of Medicine aligns with recent perspectives emphasizing the integration of career counseling for medical students into the curriculum in order to increase effectiveness.